max5522.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Maxim MAX5522
  4 * Dual, Ultra-Low-Power 10-Bit, Voltage-Output DACs
  5 *
  6 * Copyright 2022 Timesys Corp.
  7 */
  8
  9#include <linux/device.h>
 10#include <linux/kernel.h>
 11#include <linux/module.h>
 12#include <linux/mod_devicetable.h>
 13#include <linux/regmap.h>
 14#include <linux/regulator/consumer.h>
 15#include <linux/slab.h>
 16#include <linux/spi/spi.h>
 17
 18#include <linux/iio/iio.h>
 19
 20#define MAX5522_MAX_ADDR	15
 21#define MAX5522_CTRL_NONE	0
 22#define MAX5522_CTRL_LOAD_IN_A	9
 23#define MAX5522_CTRL_LOAD_IN_B	10
 24
 25#define MAX5522_REG_DATA(x)	((x) + MAX5522_CTRL_LOAD_IN_A)
 26
 27struct max5522_chip_info {
 28	const char *name;
 29	const struct iio_chan_spec *channels;
 30	unsigned int num_channels;
 31};
 32
 33struct max5522_state {
 34	struct regmap *regmap;
 35	const struct max5522_chip_info *chip_info;
 36	unsigned short dac_cache[2];
 37	struct regulator *vrefin_reg;
 38};
 39
 40#define MAX5522_CHANNEL(chan) {	\
 41	.type = IIO_VOLTAGE, \
 42	.indexed = 1, \
 43	.output = 1, \
 44	.channel = chan, \
 45	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
 46			      BIT(IIO_CHAN_INFO_SCALE), \
 47	.scan_type = { \
 48		.sign = 'u', \
 49		.realbits = 10, \
 50		.storagebits = 16, \
 51		.shift = 2, \
 52	} \
 53}
 54
 55static const struct iio_chan_spec max5522_channels[] = {
 56	MAX5522_CHANNEL(0),
 57	MAX5522_CHANNEL(1),
 58};
 59
 60enum max5522_type {
 61	ID_MAX5522,
 62};
 63
 64static const struct max5522_chip_info max5522_chip_info_tbl[] = {
 65	[ID_MAX5522] = {
 66		.name = "max5522",
 67		.channels = max5522_channels,
 68		.num_channels = 2,
 69	},
 70};
 71
 72static inline int max5522_info_to_reg(struct iio_chan_spec const *chan)
 73{
 74	return MAX5522_REG_DATA(chan->channel);
 75}
 76
 77static int max5522_read_raw(struct iio_dev *indio_dev,
 78			    struct iio_chan_spec const *chan,
 79			    int *val, int *val2, long info)
 80{
 81	struct max5522_state *state = iio_priv(indio_dev);
 82	int ret;
 83
 84	switch (info) {
 85	case IIO_CHAN_INFO_RAW:
 86		*val = state->dac_cache[chan->channel];
 87		return IIO_VAL_INT;
 88	case IIO_CHAN_INFO_SCALE:
 89		ret = regulator_get_voltage(state->vrefin_reg);
 90		if (ret < 0)
 91			return -EINVAL;
 92		*val = ret / 1000;
 93		*val2 = 10;
 94		return IIO_VAL_FRACTIONAL_LOG2;
 95	default:
 96		return -EINVAL;
 97	}
 98
 99	return -EINVAL;
100}
101
102static int max5522_write_raw(struct iio_dev *indio_dev,
103			     struct iio_chan_spec const *chan,
104			     int val, int val2, long info)
105{
106	struct max5522_state *state = iio_priv(indio_dev);
107	int rval;
108
109	if (val > 1023 || val < 0)
110		return -EINVAL;
111
112	rval = regmap_write(state->regmap, max5522_info_to_reg(chan),
113			    val << chan->scan_type.shift);
114	if (rval < 0)
115		return rval;
116
117	state->dac_cache[chan->channel] = val;
118
119	return 0;
120}
121
122static const struct iio_info max5522_info = {
123	.read_raw = max5522_read_raw,
124	.write_raw = max5522_write_raw,
125};
126
127static const struct regmap_config max5522_regmap_config = {
128	.reg_bits = 4,
129	.val_bits = 12,
130	.max_register = MAX5522_MAX_ADDR,
131};
132
133static int max5522_spi_probe(struct spi_device *spi)
134{
135	struct iio_dev *indio_dev;
136	struct max5522_state *state;
137	int ret;
138
139	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*state));
140	if (indio_dev == NULL) {
141		dev_err(&spi->dev, "failed to allocate iio device\n");
142		return  -ENOMEM;
143	}
144
145	state = iio_priv(indio_dev);
146	state->chip_info = spi_get_device_match_data(spi);
147	if (!state->chip_info)
148		return -EINVAL;
149
150	state->vrefin_reg = devm_regulator_get(&spi->dev, "vrefin");
151	if (IS_ERR(state->vrefin_reg))
152		return dev_err_probe(&spi->dev, PTR_ERR(state->vrefin_reg),
153				     "Vrefin regulator not specified\n");
154
155	ret = regulator_enable(state->vrefin_reg);
156	if (ret) {
157		return dev_err_probe(&spi->dev, ret,
158				     "Failed to enable vref regulators\n");
159	}
160
161	state->regmap = devm_regmap_init_spi(spi, &max5522_regmap_config);
162
163	if (IS_ERR(state->regmap))
164		return PTR_ERR(state->regmap);
165
166	indio_dev->info = &max5522_info;
167	indio_dev->modes = INDIO_DIRECT_MODE;
168	indio_dev->channels = max5522_channels;
169	indio_dev->num_channels = ARRAY_SIZE(max5522_channels);
170	indio_dev->name = max5522_chip_info_tbl[ID_MAX5522].name;
171
172	return devm_iio_device_register(&spi->dev, indio_dev);
173}
174
175static const struct spi_device_id max5522_ids[] = {
176	{ "max5522", (kernel_ulong_t)&max5522_chip_info_tbl[ID_MAX5522] },
177	{ }
178};
179MODULE_DEVICE_TABLE(spi, max5522_ids);
180
181static const struct of_device_id max5522_of_match[] = {
182	{
183		.compatible = "maxim,max5522",
184		.data = &max5522_chip_info_tbl[ID_MAX5522],
185	},
186	{ }
187};
188MODULE_DEVICE_TABLE(of, max5522_of_match);
189
190static struct spi_driver max5522_spi_driver = {
191	.driver = {
192		.name = "max5522",
193		.of_match_table = max5522_of_match,
194	},
195	.probe = max5522_spi_probe,
196	.id_table = max5522_ids,
197};
198module_spi_driver(max5522_spi_driver);
199
200MODULE_AUTHOR("Angelo Dureghello <angelo.dureghello@timesys.com");
201MODULE_DESCRIPTION("MAX5522 DAC driver");
202MODULE_LICENSE("GPL");